News that one of the Beijing Zoo's pandas had died wasn't released to the public until more than 20 days after its death, the Beijing Times reported.

The female panda, "Shuiling," nearly 3 years old, used to be the strongest panda in the zoo and had a healthy appetite, said a woman surnamed Lu, who goes to the zoo regularly to record the lives of the pandas with a mobile phone.

Lu said on July 2, when she saw Shuiling for the last time, the panda was out of spirits and declined to eat. She didn't turn up when Lu went to the zoo again on July 5.

Lu was told by zoo workers that the panda was reluctant to go out because of the hot weather. When she contacted the China Conservation and Research Center for Giant Pandas on Monday, she was told the panda had died on July 5.

A section chief from the zoo confirmed Shuiling's death on Wednesday, saying the panda died of shock caused by mesenteric torsion, a condition in which the intestines get twisted and begin to rot. Staff and experts tried several treatments but failed to save her life. Staff said the disease is a rare clinical case whose cause cannot be determined.

A zoo employee said they hadn't wanted to tell panda lovers the bad news, while Zhang Jinguo, vice curator at the Beijing Zoo, said the information wasn't released because they were waiting for a complete pathology report.

According to an official from the State Forestry Administration, no rule has been found yet regarding whether a panda's death should be announced immediately.

Shuiling's fur will be sent back to the base of the China Conservation and Research Center for Giant Pandas after her body is cremated and may be made into a specimen, said a staff member from the center.

The zoo's three other pandas remain in good health, according to experts.